Multifunction Imager with Switchable Polarimetry and Spectral Subsystems

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Solution Overview

Problem

Conventional imagers lack the capability to operate independently as polarimeters, spectral imagers, or cameras, and cannot selectively turn off functionality, leading to registration errors when multiple instruments are used to capture different types of images.

Innovation Solution

A multifunction imager is developed with programmable polarimetry and spectral imaging subsystems, incorporating switchable phase retarders, linear polarizers, and electrically switchable dispersers, allowing independent operation as a camera, polarimeter, spectral imager, or combinations thereof, with the ability to turn off specific functions to function as a clear aperture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple separate instruments (camera, polarimeter, spectral imager) are used to capture different types of images, then comprehensive imaging data can be collected, but registration errors occur and device complexity increases

Engineering Contradiction:
Improveimage registration accuracyVSAvoidnumber of separate instruments
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines a camera, polarimeter, and spectral imager into a single integrated multifunction imager with a shared optical train and detector array. The polarimetry subsystem includes switchable phase retarders and polarizers, while the spectral imaging subsystem includes a tunable filter, all integrated with the camera function to eliminate registration errors between separate instruments.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The imager is designed as a universal platform that can operate independently as a camera, polarimeter, spectral imager, or in combined modes. The switchable optical elements allow the system to perform multiple functions using the same hardware infrastructure, reducing the need for separate specialized instruments.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of information

If all imaging functions operate simultaneously, then comprehensive data is collected, but data collection time increases and processing becomes slower

Engineering Contradiction:
Improvecompleteness of imaging dataVSAvoiddata collection time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The system employs dynamic switching of optical elements through liquid crystal phase retarders and tunable filters that can be reconfigured in real-time. This allows the imager to adapt its configuration based on the specific imaging task, enabling rapid switching between different imaging modes without mechanical moving parts.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The switchable optical elements can be cycled through different states to collect various types of imaging data in a periodic sequence. The system can rapidly alternate between camera, polarimetry, and spectral imaging modes, collecting comprehensive data over time while maintaining high temporal resolution through the fast switching capability of the liquid crystal elements.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If switchable optical elements are used to enable independent operation of subsystems, then functional versatility is improved, but device complexity increases

Engineering Contradiction:
Improveindependent subsystem operationVSAvoidswitchable optical components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical switching mechanisms with electrically controlled liquid crystal phase retarders and tunable filters. These electro-optic elements can be switched between different states using electrical signals, eliminating the need for mechanical moving parts while enabling independent control of polarimetry and spectral imaging functions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system controls the state of optical elements by changing physical parameters such as voltage applied to liquid crystal phase retarders and filter wavelength settings. By modulating these parameters, the system can dynamically adjust the optical path to enable or disable specific imaging functions without adding complex mechanical switching infrastructure.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables simultaneous collection and processing of spatial, spectral, and polarization data on a single detector array, eliminating registration errors and allowing rapid switching between imaging modes, enhancing image recognition and reducing data collection time.

Implementation Method 1

The polarimetry subsystem includes at least one switchable phase retarder

Methodology Applied
Scientific EffectPhase retardation: Birefringence

Implementation Method 2

a linear polarizer

Methodology Applied
Scientific EffectLinear polarization filtering: Polarisation

Implementation Method 3

an electrically switchable disperser configurable between an ON state in which the disperser spectrally disperses incident electromagnetic radiation

Methodology Applied
Scientific EffectSpectral dispersion: Diffraction

Data Source

PatentEP3080569B1Multifunction imager
Publication Date: 2020.06.24 RAYTHEON CO
  • EP3080569B1 patent drawingFigure 1
  • EP3080569B1 patent drawingFigure 2
  • EP3080569B1 patent drawingFigure 3~4

AI summary

A programmable multifunction spectral and/or polarization imager. In one example, such an imager includes an imaging optical subsystem configured to receive electromagnetic radiation from a distant scene, a focal plane array configured to produce an image of the scene, and a programmable polarimetry subsystem electrically switchable between an ON state in which the polarimetry subsystem receives the electromagnetic radiation and provides polarized electromagnetic radiation to the focal plane array, and an OFF state in which the polarimetry system is configured as a first substantially clear aperture that passes the electromagnetic radiation to the focal plane array. In certain examples, the imager includes a programmable spectral imaging sub-system configurable between an ON state and an OFF state.